Just a quick idea I had -
What if there was a button that you could click when you select a player in your club that converts 1 of those cards into its power equivalent and stores it?
It would work just like how the 'Send to Transfer List' button works - you click it and it sends 1 copy of your card to be converted into power and saved to your power slot.
I'm sure this would defeat the purpose of grinding for the high tier power players but it was just a thought.
(It could also give you a certain amount of power in relation to its rating that is lower than its actual power in order to balance this feature)
Let me know what you think!